On Sun, Jul 13, 2003 at 03:32:08PM -0400, DinoBoyGraphics@aol.com
scripsit:
> P.S. In his excellent Dinosaurs of the Air, Greg Paul says that the
> only explanation for the reduction in pelvic girdle size in
> archaeopterygians and early dromeosaurs is that they were arboreal.
> Nonsense; it is equally parsimonious to assume that the terminal
> ballistic phase during terrestrial hunting had begun the switch from
> true leaping to gliding and/or active powered flapping. Once
> aerodynamic power supplants leg power, reduction of hindlimb mass
> would have enhanced the distance and control over this hunting style.
> No trees need be involved.
Especially as the second toe sickle claw a)only works down and b)has a
force limit; you can't apply more than will start shoving the dromeosaur
away from the prey.
"Hang time", and some aerodynamic means of counterbalancing a downward
force, would be selected for in any dromeosaurid that regularly hunted
large prey.
--
oak@uniserve.com | Uton we hycgan hwaer we ham agen,
| ond thonne gedhencan he we thider cumen.
| -- The Seafarer, ll. 117-118.